<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    
    <script>
      console.log(1);
      setTimeout(function () {
        console.log(3);
      }, 1000);
      console.log(2);
      //输出123 而不是132
    </script>
  </body>
</html>
